Jump to content
HybridZ

Turbo AFM vs N/A AFM Calibration


Recommended Posts

I have searched, and I have read atlanticz's spring calibration. http://atlanticz.ca/zclub/techtips/afm/calibration/index.html

 

Here are some numbers for the N/A L28 tension required for the Air Flow Meter (AFM)

 

149 ml required for swiper to reach the half-way mark. Testing my newly acquired turbo AFM there was only exactly 50ml required to move the swiper to the halfway mark. What is going on?? Is there ANY input, if someone did a picture recorded test with their turbo AFM it would save me so much time and well, is too late for money because I bought this AFM for $25...

Edited by thetremendoustim
Link to post
Share on other sites

To the people on this website: I'm sorry, my husband has actually committed suicide and left a note saying that I should update you guys on this thread. His turbo AFM problems finally got to him so badly that he had to end it all. Its too bad nobody could just simply perform this 30 minute test, this could all be over with. Now i have to clean up a mess of oil, gasoline and toasted flesh, again I'm so sorry this had to happen.

Link to post
Share on other sites

Ah yes, well, apparently, no one has an answer to your query. This is Hybridz and most people deal with upgrades and modifications that may eliminate the stock AFM. I have not heard of any instructions being available for the Turbo AFM, but if you do find them, or make some, please post them here.

 

I can't tell from your posts, or from your signature, but I am guessing you have a mostly/all stock 1975-1983 280Z/ZX N/A. If you tell us exactly what you have that would help. Also, what exactly are you trying to do? It sounds like you're upgrading from the stock N/A AFM to the turbo AFM. Is that correct?

 

As far as the swap goes, there's no exact science, and there's not gonna be any way to get it exactly right without a flow bench to put an exact amount of deflection on the door at a certain amount of airflow.

But, here's what I would recommend: Do you have a multimeter (volts/ohms)? If so, check which pins produce a varying resistance when you move the flapper (actually better would be to find out which one is the 5V power pin, apply 5V to it, then measure the Voltage at the output pin).

Like I said you won't be able to get it exactly right, because at any certain point, the bigger flapper door is going to be letting more air through and I don't know if that translates with the use of weights. So anyway, I would say use 2 points, 1 about half way, and 1 close to full open. Maybe 140ml and 280ml or something like that. Measure the resistance or voltage output on the N/A AFM for both of those points, then hang the weights on the turbo AFM and see if the R/V is close to what it was on the N/A AFM - if it's not, adjust the spring until it is. You probably won't be able to get both points exactly right, so I would go for a balance between the two.

 

That's about as scientific as I think I would get. In fact - what I would do, since you're running an N/A is get the new AFM installed, start the car, then adjust the AFM while it's running till I get a somewhat smooth idle. Then go out, make a couple of runs, come back, adjust the flapper spring one way a little bit, make some runs, then the other way a little bit and see if it gets better or worse.

 

I might be taking my turbo AFM out to install megasquirt soon, if I remember to, I'll see about performing this test.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...